The number of Irish 25 to 29-year-olds living at home has almost doubled in the last decade.
New Eurostat Data gives a figure of 68 per cent, making Ireland an outlier within Western Europe.
Education and parenting consultant Gill Hines said children are biologically ready to leave the home between the ages of 18 and 20.
"Parents treat boys different to girls. It's this feeling that men are helpless and useless, and therefore we have to look after them more," Ms Hines said.
"I think it's a global thing. If you look at statistics, women carry on doing more for their sons, then they do for their daughters. Daughters are pushed to be independent from a much younger age, and therefore are more willing to go out there.
"It's very difficult for parents and children to live together when they see each other as equal adults. Where one doesn't have the power, or one doesn't have the say, that has a cost psychologically, in terms of how young people see themselves."
